Abstract: Based on the fishing data of Chilean jack mackerel (Trachurus murphyi) obtained by Chinese large trawling fleets in the Southeast Pacific Ocean during 2003~2011 as well as the data of sea surface temperature (SST), the main fishing ground plot was drawn by software of ArcGIS10.0 by which we analyzed the relationship between monthly variation in fishing grounds positions of Chilean jack mackerel and SST. The results show that the central fishing ground moved gradually from south to northwest since March, and then removed gradually to southeast after October. The fishing grounds were mainly distributed: in the areas of 80°W~90°W, 40°S~45°S with the most suitable SST of 12~14 ℃ from March to June; in the areas of 80°W~90°W, 35°S~40°S with the most suitable SST of 13~14 ℃ from July to August; in the areas of 85°W~95°W, 30°S~35°S with the most suitable SST of 15~16 ℃ from September and October; in the areas of 90°W~95°W, 30°S~40°S with the most suitable SST of 16~17 ℃ from November to December; in the areas of 85°W~95°W, 35°S~45°S with the most suitable SST of 16~17 ℃ from January to February.